6533b870fe1ef96bd12cf099

RESEARCH PRODUCT

Reproductive phenology of submerged macrophytes: A tracker of year‐to‐year environmental variations

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AIMS: Phenological shifts are useful trackers of climate change effects on species and communities, but few datasets focus on the climate‐driven phenological responses of aquatic ecosystem vegetation. We aimed to analyse the reproductive seasonality of a submerged macrophyte community, the synchrony among coexisting species, and their responses to several environmental factors. LOCATION: A Mediterranean coastal pond in Valencia, Spain. METHODS: We analysed three years of data on a submerged macrophyte community. Plants were collected biweekly or monthly (57 collection dates) to quantify the intensity of flowering/fruiting per species. The reproductive seasonality of the community was tested with circular statistics. The reproductive synchrony of species was calculated with the Augspurger and the Freitas and Bolmgren indexes. The environmental factors driving reproduction in macrophytes were analysed with redundancy analyses. RESULTS: The reproductive activity of the community was seasonal (peaking in spring–summer) or non‐seasonal (peaking in spring–summer and autumn) depending on the year‐to‐year variations of precipitations after the summer drought. The synchronization among species in flowering and fruiting (overlap in time and intensity) was low, because the species‐specific reproductive patterns were spread throughout the long Mediterranean growing season. Temperature, water level, and conductivity were the variables that best explained flowering variability in the community, indicating that these factors affected each species differently. Fruiting was temporally correlated to flowering, with different lags depending on the species life cycle. CONCLUSIONS: The species‐specific responses suggest that a warming climate may act as an environmental filter, gradually changing the community structure. The reproductive phenology of submerged macrophytes could act as an early indicator of a changing climate, with charophytes (Characeae) as suitable tracker candidates. Further studies concerning their phenology are needed to assess the resilience of submerged macrophyte communities to drought and assure the long‐term functioning of Mediterranean aquatic ecosystems.